I. Field of the Invention
This invention relates to blast gauges and particularly to a non-directional gauge for blast measurements.
II. Description of Known Art
Measurement of blast involves the insertion of an instrumented body into the flow field. Gauges of this type are known which feature a conventional pressure transducer housed within a streamlined fairing. The fairing is designed to cause minimal perturbation of the blast field being measured. Such known gauges only function accurately when aligned in such a way that the incident blast wave traverses the face of the transducer at grazing incidence. Such alignment requires advance knowledge of the direction of travel of the blast wave.
When measurements of blast waves are made in enclosed surroundings, such as rooms, both direct and reflected waves are produced which travel in different directions. A gauge may be set to measure one of the waves, but it will be misaligned with respect to most of the other waves that arise. The measurement of the reflected waves is most important as they may interact and comprise a stronger force than the initial wave. If a reflected wave should arrive at right angles to the face of the transducer in such a gauge, the perceived pressure could be more than double the true static value. It is clear that such directional blast gauges are of little value when blast measurements need to be made in enclosed surroundings.